She added that she hoped the family would take care of the boy's twin sister they took with them.

Gammy was separated from his healthy twin sister

Pattaramon Chanbua, a 21-year-old food vendor in Thailand's seaside town of Sri Racha, has had to take a break from her job to take care of her seven-month-old surrogate baby, named Gammy, who also has a congenital heart condition.

The boy, with blond hair and dark brown eyes, is now being treated in a hospital for infection in his lungs.

Ms Pattaramon said she met the Australian couple once when the babies were born and knew only that they lived in Western Australia state.

"I've never felt angry at them or hated them. I'm always willing to forgive them," Ms Pattaramon told. "I want to see that they love the baby girl as much as my family loves Gammy. I want her to be well taken care of."

Gammy was separated from his healthy twin sister

Ms Pattaramon was promised 300,000 baht (£5,500) by a surrogacy agency in Bangkok, Thailand's capital, to be a surrogate for the Australian couple, but she has not been fully paid since the children were born last December.

She said the agency knew about Gammy's condition four to five months after she became pregnant but did not tell her. It was not until the seventh month of her pregnancy when the doctors and the agency told her that one of the twin babies had Down's syndrome and suggested that she have an abortion just for him.

Ms Pattaramon recalled strongly rejecting the idea, believing that having the abortion would be sinful. "I asked them, 'Are you still humans?' I really wanted to know," she said.

Her case highlights the rising problem of surrogacy in Thailand, where legal loopholes allow the practice to exist. Thai officials said last week that there were 50 surrogate babies of Israeli couples in Thailand who were not able to travel to Israel due to nationality issues.

"The Thai authorities are pushing for a law that will ban surrogacy of non-family members, but there is no punishment right now," said Pavena Hongsakul, a former Thai social development and human security minister and advocate for women's and children's rights. "This is a worrying trend as it can lead to other problems, such as human trafficking."

Ms Pavena said a surrogate mother is usually paid 300,000 to 350,000 baht (£5,500 to £6,500) to carry a baby for overseas couples who either have reproduction difficulties or are gay.

Ms Pattaramon, who also has a six-year-old son and a three-year-old daughter, said she approached the surrogacy agency on Facebook early last year because she wanted money to pay off debts. She said she plans to file a complaint with Thai police to get the rest of the unpaid compensation money from the agency.

Meanwhile, an online campaign by an Australian charity organization to help Gammy has raised nearly 200,000 US dollars (£119,000) since July 22.

"I'm going to save the money for him," Ms Pattaramon said. "Actually, I just want the baby to have a house. It doesn't have to be big. I only want him to live in a good house and be comfortable."